For example, as a positioning device for measuring the position of a subject vehicle, a car navigation device or the like includes a subject vehicle position estimation device. The subject vehicle position estimation device of a car navigation device specifies a road in which the subject vehicle is traveling through map matching processing using information of an absolute position of the subject vehicle obtained using a GNSS receiver, information of a relative position (positional change) of the subject vehicle observed by an autonomous sensor, and map information containing data of a road network.
A subject vehicle position estimation device of the related art uses map information in which each road is represented as one link. Hence, even when highly precise positioning capable of specifying a traffic lane (lane) in which a subject vehicle is traveling is conducted, information of a lane is not reflected in the results of the map matching processing. Therefore, positioning precision of a subject vehicle position has sufficed to be a road-level precision (positioning precision of several meters). However, as a result of enhancement in performance of a car navigation device, higher accuracy in map information, development of automated driving technologies, and the like, there have been proposed technologies of specifying a subject vehicle position with higher precision (e.g., Patent Documents 1 to 3 below).